For example, the background art discloses a power supply system including a switching power supply. The power supply system disclosed in Patent Document 1 includes a switching power supply, and a control device configured to control the switching power supply. Also, the switching power supply includes a rectifying-and-smoothing circuit connected to an AC power supply, a transformer, a FET connected to a primary coil of the transformer, and a control IC. The control IC is configured to be activated as power is supplied thereto from the AC power supply. The control IC is configured to oscillate a primary side of the transformer and to induce a voltage to a secondary side of the transformer by switching the FET. The control device is configured to shift the switching power supply to an output stop mode by outputting a control pulse signal to the control IC and stopping the oscillation of the transformer during an output mode in which the transformer is oscillated and a voltage is supplied.